2.1 - 2.3 Review

How do you find the constant of variation given a set of ordered pairs?

Divide the y value by the x value k = y/x

Parallel lines have slopes that are ____________.

Equal

How do you use the vertical line test to determine if a graph is a function?

If any vertical line drawn through the graph hits more than one point on the graph, it is not a function.

What is the slope of all vertical lines?

No slope or undefined slope

What point is always on a direct variation graph?

The origin or (0, 0)

How can you tell if a set of ordered pairs is a function?

There is no repeated x value

Find the slope of the line y - 8 = -3(x + 4)

This equation is in point slope form. The slope is the value in the m position. The slope in this equation is -3.

Find the slope of the line that passes through these 2 points (-6,2) (-6-9)

Undefined since there is 0 in the denominator

Find the variation constant if the direct variation equation is 7x + 8y = 0

k = -7/8 Put the equation in y = kx form by solving for y. This gives you y = -7/8x

Perpendicular lines have slopes that are ________.

opposite reciprocals

Write the equation of a vertical line that goes through the point (-4, -1).

x = -4 Graph the point. Draw a vertical line through it. Notice that every point on the line has an x value of -4.

Find the x intercept of the line 2x + 4y = 8

x = 4 or (4, 0) Let y = 0 and solve for x.

What is point-slope form?

y - y₁ = m (x - x₁)

Find the y-intercept of the line 9x + 3y = -36

y = -12 or (0, -12) Let x = 0 and solve for y.

Write a direct variation equation in the form y = kx for the function that passes through the point (-3, 9).

y = -3x Find k by dividing y by x

Write the equation of a horizontal line that goes through the point (8 , 2).

y = 2 Graph the point. Draw a horizontal line through it. Notice that every point on that line has a y value of 2.

Write the equation of the line that is parallel to y = 4x - 1 and goes through the point (-2 , 3),

y = 4x + 11 Start in point slope form. Since the line is parallel to the given line, use the same slope, which is 4 in this case.

What is the form of a direct variation equation?

y = kx

What is slope-intercept form?

y = mx + b

What is the slope of all horizontal lines?

0 slope

Find the slope of the line that passes through these 2 points (8, 6) and (2, 5)

1/6 Use the slope formula

What is standard form?

Ax + By = C

Find the slope of the line 8x + 4y = 32

Divide the opposite of the A value by the B value. Slope = -2